Commit cad0a5c7 authored by Thierry Reding's avatar Thierry Reding Committed by Greg Kroah-Hartman
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usb: host: xhci-tegra: Implement basic ELPG support 



This implements basic engine-level powergate support which allows the
XUSB controller to be put into a low power mode on system sleep and get
it out of that low power mode again on resume.

Based on work by JC Kuo <jckuo@nvidia.com>.

Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20191206140653.2085561-11-thierry.reding@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9ccae88e

drivers/usb/host/xhci-tegra.c

+119 −8
Original line number Diff line number Diff line
@@ -1447,6 +1447,45 @@ static int tegra_xusb_remove(struct platform_device *pdev) 
}



#ifdef CONFIG_PM_SLEEP

static bool xhci_hub_ports_suspended(struct xhci_hub *hub)

{

	struct device *dev = hub->hcd->self.controller;

	bool status = true;

	unsigned int i;

	u32 value;



	for (i = 0; i < hub->num_ports; i++) {

		value = readl(hub->ports[i]->addr);

		if ((value & PORT_PE) == 0)

			continue;



		if ((value & PORT_PLS_MASK) != XDEV_U3) {

			dev_info(dev, "%u-%u isn't suspended: %#010x\n",

				 hub->hcd->self.busnum, i + 1, value);

			status = false;

		}

	}



	return status;

}



static int tegra_xusb_check_ports(struct tegra_xusb *tegra)

{

	struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);

	unsigned long flags;

	int err = 0;



	spin_lock_irqsave(&xhci->lock, flags);



	if (!xhci_hub_ports_suspended(&xhci->usb2_rhub) ||

	    !xhci_hub_ports_suspended(&xhci->usb3_rhub))

		err = -EBUSY;



	spin_unlock_irqrestore(&xhci->lock, flags);



	return err;

}



static void tegra_xusb_save_context(struct tegra_xusb *tegra)

{

	const struct tegra_xusb_context_soc *soc = tegra->soc->context;
@@ -1481,31 +1520,103 @@ static void tegra_xusb_restore_context(struct tegra_xusb *tegra) 
	}

}



static int tegra_xusb_suspend(struct device *dev)

static int tegra_xusb_enter_elpg(struct tegra_xusb *tegra, bool wakeup)

{

	struct tegra_xusb *tegra = dev_get_drvdata(dev);

	struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);

	bool wakeup = device_may_wakeup(dev);

	int err;



	/* TODO: Powergate controller across suspend/resume. */

	err = tegra_xusb_check_ports(tegra);

	if (err < 0) {

		dev_err(tegra->dev, "not all ports suspended: %d\n", err);

		return err;

	}



	err = xhci_suspend(xhci, wakeup);

	if (err < 0)

	if (err < 0) {

		dev_err(tegra->dev, "failed to suspend XHCI: %d\n", err);

		return err;

	}



	tegra_xusb_save_context(tegra);

	tegra_xusb_phy_disable(tegra);

	tegra_xusb_clk_disable(tegra);



	return 0;

}



static int tegra_xusb_resume(struct device *dev)

static int tegra_xusb_exit_elpg(struct tegra_xusb *tegra, bool wakeup)

{

	struct tegra_xusb *tegra = dev_get_drvdata(dev);

	struct xhci_hcd *xhci = hcd_to_xhci(tegra->hcd);

	int err;



	err = tegra_xusb_clk_enable(tegra);

	if (err < 0) {

		dev_err(tegra->dev, "failed to enable clocks: %d\n", err);

		return err;

	}



	err = tegra_xusb_phy_enable(tegra);

	if (err < 0) {

		dev_err(tegra->dev, "failed to enable PHYs: %d\n", err);

		goto disable_clk;

	}



	tegra_xusb_config(tegra);

	tegra_xusb_restore_context(tegra);



	return xhci_resume(xhci, false);

	err = tegra_xusb_load_firmware(tegra);

	if (err < 0) {

		dev_err(tegra->dev, "failed to load firmware: %d\n", err);

		goto disable_phy;

	}



	err = __tegra_xusb_enable_firmware_messages(tegra);

	if (err < 0) {

		dev_err(tegra->dev, "failed to enable messages: %d\n", err);

		goto disable_phy;

	}



	err = xhci_resume(xhci, true);

	if (err < 0) {

		dev_err(tegra->dev, "failed to resume XHCI: %d\n", err);

		goto disable_phy;

	}



	return 0;



disable_phy:

	tegra_xusb_phy_disable(tegra);

disable_clk:

	tegra_xusb_clk_disable(tegra);

	return err;

}



static int tegra_xusb_suspend(struct device *dev)

{

	struct tegra_xusb *tegra = dev_get_drvdata(dev);

	bool wakeup = device_may_wakeup(dev);

	int err;



	synchronize_irq(tegra->mbox_irq);



	mutex_lock(&tegra->lock);

	err = tegra_xusb_enter_elpg(tegra, wakeup);

	mutex_unlock(&tegra->lock);



	return err;

}



static int tegra_xusb_resume(struct device *dev)

{

	struct tegra_xusb *tegra = dev_get_drvdata(dev);

	bool wakeup = device_may_wakeup(dev);

	int err;



	mutex_lock(&tegra->lock);

	err = tegra_xusb_exit_elpg(tegra, wakeup);

	mutex_unlock(&tegra->lock);



	return err;

}

#endif

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